Abstract

Self-assembledquantum dots(QDs) in an InAlGaAs matrix on InP (001) substrates were grown by the alternate growth method (AGQD), where an InAs layer with a thickness of 1 monolayer (ML) and an InAlGaAs layer with a thickness of 1 ML were alternately deposited. Cross-sectional transmission electron microscopy images indicated that the aspect ratio (height/width) for the AGQDs was , which was higher than of conventionally grownInAsQDs. The photoluminescence(PL) peak position for the ground states of the AGQDs was with a linewidth broadening of at room temperature, while the PLlinewidth for the conventionally grownQDs was . And the peaks for the excited-state transitions were also clearly observed from the excitation-power dependent PL. This is the first observation on the well-defined excited-state transitions from the InP-based InAsQDs, even though there were several reports on the features of the excited states.